Although automated soldering is widespread, a significant number of soldering tasks must still be done manually. With manual soldering, it necessary to prevent the accumulation of smoke and fumes from work stations occupied by workers. The amount and concentration of smoke and fumes can vary depending on the type and volume of manual soldering tasks. Fans have been used to remove smoke and fumes, but conventional fans are often not suited for a broad range of situations. In some work conditions, smoke and fumes are generated close to a fan, so a low amount of suction is needed. In other work conditions, a greater amount of suction is needed to remove smoke and fumes generated far from the fan. Fan rotation speed may be increased to create greater suction, but this may significantly increase the amount of noise from the fan. Also, smoke and fumes can be concentrated and may be removed more efficiently with a fan having a relatively small suction opening. Furthermore, smoke and fumes can be widely dispersed and may be removed more efficiently with a fan having a large suction opening for moving a greater volume of air.
Accordingly, there is a need for a fan assembly that has more than one mode of operation to allow efficient removal of smoke and fumes in a variety of work conditions. There is also a need for a fan assembly that can easily be adjusted to operate in different modes. There is a need to accomplish such adjustment without complex mechanisms and electronic circuitry. Such mechanisms and electronic circuitry increase manufacturing costs and are subject to failure over time.